Kirsty Neaylon – Department of Horticulture, Viticulture & Oenology, University of Adelaide

Many species from the genus Eucalyptus have economic potential for the ornamental horticulture industry, including E. erythronema, E. stricklandii and E. ‘Urrbrae Gem’.  To bring these plants into cultivation propagation techniques must be developed other than the more conventional seed methods.  Vegetative propagation involves the multiplication of an individual plant into a series of plants, genetically identical with the parent and each other. The advantage of vegetative propagation is that desirable features can be maintained and reproduced. Seed generated plants are variable as a result of natural outcrossing mechanisms. In addition, plants that are vegetatively propagated generally flower much younger, which is especially important for commercial sales. Successful vegetative propagation of adult trees will enable the clonal reproduction of plants that have shown outstanding ornamental characteristics.

The selection of certain individuals that can be successfully vegetatively propagated is crucial to reduce the lengthy selection processes normally associated with trees. Molecular genetic maps provide large amounts of information that can be used to identify traits of interest. Mapping strategies for quantitative trait loci (QTLs) involve the construction of genetic linkage maps of molecular markers and the identification of QTLs for individual genotypes. Detection of traits relating to vegetative propagation in ornamental eucalypts will provide valuable ways of identifying plants that can be successfully propagated.

Tremendous scope exists for the development of eucalypts through the creation of hybrids and the selection of particular cultivars using vegetative propagation techniques. Development of these techniques will greatly increase the range of plants available for the horticulture and floriculture industries. However, unless efficient vegetative propagation techniques are developed, these plants have no commercial future.

The aim is to develop successful vegetative propagation techniques for ornamental eucalypts. A variety of propagation techniques are being used, including cuttings, grafting, budding and aerial layering. In addition, the detection of genes associated with vegetative propagation will provide a way of identifying plants that can be readily propagated.